Blowing of articles



P 1951 H. B. MORRIS 2,568,129

BLOWING OF ARTICLES Original Filed May 15, 1947 fly yfinial/11111111111111; 7 4 1 IN V EN TOR. HAROLD B. MORR/J BY ATTORNEYPatented Sept. 18, 1951 zstai t r 2,568,129 BLOWING or ARTICLES HaroldB. Morris, Ashland, Ohio, assignor to Eagle Rubber Company, Inc.,Ashland, Ohio, a corporation of Delaware Original application May 15,1947, Serial No.

748,265. Divided and this application Decemher a, 1949, Serial No.130,961

3 Claims. (01. 1s s.7)

This invention relates to the blowing of articles of rubber and otherelastomers.

In carrying out the invention a form for a balloon or the like iscovered with an elastomer,

as by dipping the form into a dispersion or solution of the elastomer,the deposit of the elastomer is cured on the form and then .is blownfrom it. .The inflation of the cured article on the form serves as ameans for detecting imperfect articles which contain pinholes or thelike, and separating these from articles which are free from pinholes.The perfect articles are blown from the forms, and the imperfect onesburst and are scrapped. This eliminates the usual inspection step. Todetect pinholes and other minor deflects the article should be infiateduntil its surface is at least doubled. Thus, in this process the articleis automatically inspected and removed from the dipping form.

The invention will be further described in connection with the drawings,in which- Fig. 1 is a section of a form covered by a deposit of latexformed by dipping;

Fig. 2 shows the same after the formation of a bead on the dippedarticle;

Fig. 3 illustrates the process of inflating the article;

Fig. 4 illustrates the completely inflated article partially removedfrom the form;

Fig. 5 illustrates how the article is blown from the form; and

Fig. 6 is a detail showing a preferred type of perforation in the end ofthe form.

Although in the detailed discussion of the invention given herein, theinvention will be described more particularly in connection with adipping operation in which the form is first dipped into a coagulant andthen into latex, it is to be understood that the invention is notlimited to formation of the deposit of the elastomer by dipping. If thedeposit be formed by dipping any of the various commercial types ofdipping may be employed, whether or not a coagulant be employed andwhether the form be dipped in a dispersion or a solution of theelastomer. The form may be of aluminum, but it is to be understood thatthe invention is not limited thereto, as glass and porcelain forms andother commercial forms may be used. The forms shown are of simpleconfiguration. More complicated forms may be employed in carrying outthe invention. The forms may be of paddle design, or they may be shapedas desired to form a balloon or other article of simple outline, or theymay be shaped to form balloons and the like of more intricate designswhich represent animals, etc. Although air is mentioned as the inflatingmedium, other fluids may be used. Thus, the invention is not limited tothe details of the illustrations which follow.

In Fig. l a form I which generally cylindrical in shape is shown mountedon a base 2. This form may be one of many in a bank of forms. Theseforms may be located close to one another, as is the usual practice atthe present time, but they are preferably spaced so that the inflatedarticles will just touch or will not quite touch one another. If contactof the cured articles on inflation is not detrimental, such spacing isno essential. The line 3 passes from a source of compressed air throughthe length of the form to the opening 4, which is at the end of the formwhich first comes into contact with the dipping bath when the forms aredipped vertically.

Although the drawings do not illustrate the layer of coagulant which maybe under the clipped film, it is understood that in a preferred methodof dipping into latex the deposit 5 is formed by dipping the form Ifirst in a coagulant and then in a suitably compounded latex. Thecoagulant may contain talc or other lubricant to prevent adherence-ofthe deposit to the form.

After dipping and obtaining the deposit 5, the narrowed portion 6 of thedeposit which is to form the neck of a balloon, is rolled from the baseforward as is customary to form the bead or ring I. This is illustratedin Fig. 2.

After rolling, the balloon is cured. This may be done by passing theform with the deposit on it, through a curing oven, as is commoncommercial practice. Any method of curing on the form may be employed.If the balloon is to be dried or cured in a high frequency field, theform is made of glass or porcelain or other dielectric.

After curing, the balloon is inflated. At present it is customary tostrip the cured balloon from the form and then inflate for inspection bymanually placing the balloon over a nozzle which is connected with asource of compressed air. This is a time-consuming operation. By blowingthe article while on the form the inspection is automatic. If thedeposit is faulty for any reason so that it cannot be inflated, it willremain on the form when the air pressure is turned on. If there is aweak spot in the balloon it will explode when inflated and the remnantsof the exploded balloon may be retained on the form but in a deflatedcondition.

Inflation which doubles the area of the balloon will expose most weakspots. Inflation to several times the original size of the balloon willbe usual. The degree of inflation will depend upon such factors as thetensile stress of the elastomer, the deposit thickness, the percent thebead or neck of the article, if any, must be stretched to be removedfrom the form, etc. If there are no imperfections in the balloon, itautomatically passes inspection and will be blown from the form. Thusthe process includes automatic inspection and Stripping from the form.

Fig. 3 illustrates, in dotted lines, how, on inflation, the end of theballoon may first become enlarged. Or the balloon may be lifted aminimal amount from the form and then start to inflate in the center orelsewhere. The inflation continues along the form until the entireballoon to the bead 1 is inflated. After the whole balloon has becomeinflated to the extent necessary to enlarge the bead 1 so that itembraces the portion of the form of largest diameter, the air pressurewill lift the bead from the form sufficiently to allow a thin film ofair to pass under the bead, and when this takes place the finishedballoon 5 will be ejected from the form as shown in Fig. 4. Immediatelyafter leaving the form, the balloon starts to deflate and Fig. 5 showsit in a partially deflated condition.

It will be understood that when the form is dipped, in coagulant, andlater dipped in latex, plugs of th coagulant and/or latex may form inthe opening 4. If the portion of the plug which is formed by the latexis of any substantial thickness, it will be apt to become compressed bythe pressure of the compressed air against it, and this will enlarge itsdiameter. Thus, when the air is turned on, the plug will tend to becomemore tightly wedged in the opening. 'Fig. 6 shows a preferred form ofopening in which the wall I!) of the opening is conical.

In all of the drawing the compressed air passage is enlarged tofacilitate illustration. In actual practice the size of the opening 4 orIn will usually not exceed a small fraction of an inch in diameter,although the form may be as much as a foot or so in length, or it may bea small form not over an inch or two in length.

Thus, the process may be used for the inspection and removal of balloonsand other articles .4 manufactured by curing an elastomer deposit on aform. The process is applicable to dipping in either a solution ordispersion of the elastomer.

This application is a division of my application Serial No. 748,265filed May 15, 1947.

The invention is defined in the appended claims.

WhatIclaim is:

1. The method of preparing and automatically inspecting elastomerarticles which comprises forming a layer of elastomer on each form in abank of forms, rolling a bead at the edge of each layer where each formenters its article. curing the elastomer layers, and then introducingair under pressure through each form into each article at a point awayfrom where the form enters the article thereby inflating the imperforatearticles.

2. The method of preparing and automatically inspecting balloons whichcomprises forming a layer of elastomer on each form in a bank of forms,each form including neck by which the form is supported and a part ofwhich is covered by the elastomer layer, rolling a bead at the edge ofthe layer on the neck, curing the elastomer layers, and then introducingair under pressure through the respective forms into each balloon at apoint away from the neck thereby inflating the imperforate balloons andthen blowing them from their forms in air-inflated condition, and thusseparating imperforate balloons from perforat balloons.

3. The method of preparing and automatically inspecting an elastomerarticle which comprises forming a layer of elastomer on a form, rollinga bead at the edge of the layer where the form enters the article,curing the elastomer layer, and then introducing air under pressurethrough the form into the article at a point away from where the formenters the article, thereby inflating the imperforate article.

HAROLD B. MORRIS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,217,213 Bratring Oct. 8, 19402,508,204 Weber May 16, 1950

1. THE METHOD OF PREPARING AND AUTOMATICALLY INSPECTING ELASTOMERARTICLES WHICH COMPRISES FORMING A LAYER OF ELASTOMER ON EACH FORM IN ABANK OF FORMS, ROLLING A BEAD AT THE EDGE OF EACH LAYER WHERE EACH FORMENTERS ITS ARTICLE CURING THE ELASTOMER LAYERS, AND THEN INTRODUCING AIRUNDER PRESSURE THROUGH EACH FORM INTO EACH ARTICLE AT A POINT AWAY FROMWHERE THE FORM ENTERS THE ARTICLE THEREBY INFLATING THE IMPERFORATEARTICLES.